The
splendor of a star-filled sky pales in comparison to what human vision
is unable to record about the Universe. This site provides a striking
aural analogy to the impoverished view our eyes provide.

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Our eyes are extraordinarily
limited instruments with which to observe the Universe. As vision evolved
over the past several hundred million years, it has become carefully
tuned to the most abundant kind of radiation around -- the kind we parochially
call light. The qualities of this radiation are determined by just two
numbers: the temperature of the surface of the Sun, and the strength
of gravity on the surface of the Earth.

At 5800 degrees,
the atoms in the solar atmosphere are dashing about with velocities
such that, when they encounter each other, most radiate waves of electromagnetic
energy with spacings between crests -- wavelengths -- of roughly 10
to 50 millionths of an inch. When these waves (moving at 186,000 miles
per second) hit Earth's atmosphere after their eight-minute journey
from the Sun, the ones with wavelengths shorter than 15 and longer
than 30 millionths are absorbed in the air and never reach the ground.
The strength of the Earth's gravitational pull controls which types
of gas atoms our atmosphere retains, which in turn determines its
transparency to the Sun's radiation.

Thus, our eyes
have, through natural selection, become attuned to just a single octave
(a factor of two in wavelength) of electromagnetic waves. All the
colors of the rainbow -- colors simply being the manifestation of
different wavelengths of radiation -- fall in this single octave.
Red, orange, yellow, green, blue, indigo, and violet are analogous
to the seven notes between middle C on a piano and the C an octave
higher.

But the Universe
is not constrained to our rainbow of colors. There are regions of
space where the temperature is hundreds of degrees below zero, and
others where it is a million times hotter than the Sun. Atoms in these
regions radiate wavelenths ranging from miles to quadrillionths of
an inch -- in all, over 50 octaves. And to all of these octaves but
one, our eyes -- and the giant optical telescopes we use to expand
the size of our eyes -- are completely blind.

Looking at the
Universe with our natural radiation detectors, then, gives us a highly
biased and impoverished view. Our ears can detect a full ten octaves
of sound waves, giving us a much richer aural picture of the world.
Imagine listening to Beethoven's Ninth Symphony and only being able
to hear a single octave. Or better yet, listen here to the Ode to
Joy one octave at a time, and experience how much we are missing of
the Universe by using only our single-octave filters. And while you
are listening, see what the most familiar object in the sky -- the
Sun -- would look like if you could see as much of the electromagnetic
spectrum as you can hear of the sound spectrum.